1. Field of the Invention
This invention relates generally to an apparatus that exerts torsional resistance upon a clockwise or counterclockwise rotating object. More particularly, but without limitation thereto, the invention relates to a steering system for remotely controlling an object and in particular an apparatus that simulates realistic steering feel in a remote control steering system by providing torsional resistance and a "center return" feature.
2. Description of the Related Art
Steering devices associated with remote vehicle control provide two basic forms of bidirectional (clockwise and counterclockwise) torsional resistance to steering motion. In FIG. 1 the first of these methods is shown in which a pair of counteracting springs act upon the rotational axis of a remote control steering column. A common mode of failure of this system is the breaking of the cable attaching the springs to the steering column. The cable is prone to corrosion and is frequently stretched over a small radius precipitating cable fraying and eventual breakage. Cable replacement can be difficult as the utilized springs are often required to be prestressed or stretched before cable attachment.
In this system the size of the springs and length of the accompanying cable can take up a considerable amount of space depending upon the amount of pressure/resistance and rotational range required of the steering column.
In a second method air-filled pistons are used instead of springs. This method, shown in FIG. 2, uses the counteracting pistons to provide torsional resistance and self-centering capability to simulate driving feel. The air-filled pistons may require pressurization to create a preload and, of course, can be prone to leakage. Typically such air-filled pistons require a considerable amount of space.